Does anyone know what causes a stagnant water smell in shower drains?

[FimboBBINGFORAPPLES]

There doesn't appear to be anything blocked, have done the bicarb and vinegar thing and its still smelly? Any ideas?

No idea what's causing it but soda crystals - a whole bag - and gallons of scalding hot water always works to clean drains.

thanks dog

Soda crystals are fab

Can you buy them in supermarkets?

Yes usually in the stain removal and washing powder aisle. Think the bag is either green or blue?

Uses for soda crystals

soda crystals in a bag

The bag is green!

Biological washing powder and gallons of boiling water removes this smell too - it's basically caused by biolgical matter decomposing/associated germs breeding - so bio-washing powder zaps it!

Fantastic - thank you all soooo much. I lurve MN.